1. Field of the Invention
The present invention relates to chucks for machine tools or the like which permit indexing the chuck and workpiece 180.degree. to permit machining both ends of the workpiece.
2. Description of the Prior Art
Various indexing chucks have been advanced in the prior art. For example U.S. Pat. No. 3,879,045 issued to Benjamin et al. shows a chuck body using jaws for holding the workpiece that are actuable under fluid pressure, and which can be indexed 180.degree. to permit the opposite ends of the workpiece to be machined without unchucking the workpiece. This patent relates primarily to a position sensor for indicating the position of the jaws during operation.
U.S. Pat. No. 4,209,181 to Morawski shows a chuck that has opposed jaws that can reciprocate toward and away from each other to grip and release a workpiece, and which are rotatable about an axis transverse to the normal machining or turning axis for indexing the chuck to different positions. This is to permit machining holes for projections on the workpiece at various indexed positions.
U.S. Pat. No. 3,790,181 shows a swivel chuck for machining workpieces, and which indexes at 180.degree. relative to the rotational axis of the workpiece during machining which will permit working on both ends of the workpiece, but again this device includes hydraulic chuck actuators, and the rotation of the chuck for indexing, and as disclosed, is accomplished using a gear drive.
U.S. Pat. No. 3,841,781 issued to Mengeringhausen shows an apparatus for the production of connectors for space frameworks, and permits indexing the connectors (workpieces) for machining to various positions about two mutually perpendicular axes, in order to accomplish the necessary machining positions in operation.
U.S. Pat. No. 3,630,536 issued to Scharfen shows a rotatable chuck, especially for lathes, which chucks workpieces and will permit indexing them 180.degree., and which is controlled by use of a cam arrangement for properly holding the chuck and releasing it at the appropriate times for operation.
An early form of a reversible chuck is shown in U.S. Pat. No. 799,006 issued to Kempster. This particular chuck has a frame that pivots downwardly from a working position to permit indexing the jaw carrier, which carries jaws for chucking the workpiece 180.degree..
However, none of the devices disclosed in such prior art provide for positive holding of the workpiece, positive drive of the chuck carrier, nor safe reliable operation as with the construction of the present device.